I just booked a flight PWM->MKE->PWM for the week of 4/18, and the outbound leg showed "R" as the class for the PWM->DTW and DTW->MKE segments. When the email ticketing confirmation arrived, though, the first leg was "Y" and the 2nd "P" (in First). Don't know what's going on that week, but apparently there ain't no coach seats to be had getting from DTW to MKE at 9:13AM on Monday . . .